Hypotensive effect of Laurelia sempervirens (Monimiaceae) on normotensive rats

Abstract

The leaves of Laurelia sempervirens (Monimiaceae), an endemic Chilean tree known as Laurel, were used by the Mapuche Amerindians for treating headache and as a diuretic. Intravenous administration of a hydroalcoholic L. sempervirens extract to rats, elicited a hypotensive response of -27.0%±2.0% in the mean blood pressure of normotensive animals at a dose of 5 mg crude extract ± kg body weight. Bioassay-guided isolation of the active Laurel metabolites led to the alkaloid laurotetanine as the main hypotensive principle of L. sempervirens leaves. At 1 mg/kg body weight, laurotetanine produced a hypotensive response of -29.0%±2.1% in the mean blood pressure of normotensive rats, with a duration of 2 min, both comparable to those elicited by the crude extract at 5 mg/kg. In the acute oral toxicity study, Laurel proved to be a very low toxicity crude drug at doses up to 3 g crude extract/kg body weight. The data obtained support the use of L. sempervirens in Mapuche traditional medicine.